Gentoo is a free operating system based on either Linux or FreeBSD that can be automatically optimized and customized for just about any application or need. Extreme configurability, performance and a top-notch user and developer community are all hallmarks of the Gentoo experience. Thanks to a technology called Portage, Gentoo can become an ideal secure server, development workstation, professional desktop, gaming system, embedded solution or something else -- whatever you need it to be. [Source]